Origen

The Old English word foul comes from an ancient root shared by Latin pus (adopted into late Middle English) Latin putere ‘to stink’ (source of LME putrid), and the original sense was ‘stinking or disgusting’. Foul play indicating unfair conduct or treachery is recorded from the late 16th century, and sports players have been able to complain of ‘a foul’ since the 1750s. See also fair